Food, urine, and feces as radiation shield for Mars mission

NewImage The Inspiration Mars team planning to send a couple on a fly-by mission to Mars in 2018 have an idea of how to protect the astronauts from cosmic rays on the long journey: pack the walls of the spaceship with food, shit, and piss. "Dehydrate (the human waste) as much as possible, because we need to get the water back," team member Taber MacCallum told New Scientist. "Those solid waste products get put into a bag, put right back against the wall… (Also,) food is going to be stored all around the walls of the spacecraft, because food is good radiation shielding." The food he adds, would block the cosmic rays but wouldn't become radioactive itself.


  1. Totally right that food is good radiation shielding. Long carbon chains in lipids are good at stopping beta particles without re-emitting any other type of radiation. Plastics are even better. Remember that next time some moon hoaxer says the moon missions had nothing but a few sheets of plastic as shielding. Plastic is good shielding for the types of radiation that can cause the worst damage to humans.

  2. “The food would block the cosmic rays but wouldn’t become radioactive itself.”
    It kinda of depresses me that physics this basic needs to be explained. (I guess the thinking is that people are used to radiation dangers referring to fallout incidents, such as from power-plants.)

    1. Before you get too depressed and too happy about your physics acumen, you might want to read up on bremsstrahlung.

      1. Bremsstrahlung is a problem with beta rays hitting metals which then immediately emit X-rays. Low power x-ray machines like at the dentist fire an electron gun at a lead target. X-rays come out and most of the rays not going all in one direction are stopped by leaded glass.

        if you are talking about something becoming radioactive I believe you are thinking of neutron absorption.

        One thing I liked about Al-Jazeera’s coverage of the reactor accident in Japan is that they always made a clear distinction between “radiation” and “release of radioactive material”. The former is a threat only if you were very near the plant. The latter is much more serious, as ingestion of even a small amount of radioactive material can have serious health consequences.

        1. The full quote from the article was “This wouldn’t be dangerous as the food would merely be blocking the radiation, it wouldn’t become a radioactive source.”  What I think he’s emphasizing is that food and water are good, but that metal isn’t always ideal radiation shielding due to bremsstrahlung.  Most of us think of ships as being built of metal.  In actuality they all would emit bremsstrahlung, hence being sources of radiation, but that emitted by metal would be more dangerous as it would be shorter wavelength and more penetrating. So I believe he is referencing a finer point of radiation protection, and not just dumbing it down to talk to the yokels. 

      2. You shouldn’t assume everyone else is motivated by smugness, it reflects poorly on you. Your guess as to how to interpret the quote is not mine.

        1. Likely so, I may be reading mustache twirling and evil grimacing into it that was not your intention.  I don’t know why I would misconstrue your motives, Mr. Archvillain.

          1. Fair enough. For the record, the context I was cuing off was “cosmic rays”. I associate beta more with solar activity, which they talked about separately.
            (Yes I know about secondary particles from cosmic radiation. I’ve built weapo^D^D^D instruments to harnes^D^D^D detect them. *mustache twirl* )

          2. I’m actually quite grateful for your comment, as it allowed me to work the word “bremsstrahlung” into a sentence.  Almost as pleasurable as when I was able to namedrop the only known non-human reservoir of Hansen’s disease, when the topic came up at a family gathering.  Armidilloes, if you were wondering. 

  3. in the freaky sci-fi short story “Scanners Live in Vain” c1950 Cordwainer Smith writes about early efforts of space travel wherein space itself induced intractable pain, so there were ostensibly two solutions: either a space-traveler had all their sensory nerves surgically cut (producing a “Haberman”) or one could line the walls of one’s space-ship with living ‘oysters’, which grow to confluence, and they would absorb the pain ..fields(?).   So just replace oysters with excreta and Cordwainer’s quirky genius is sort’ve realized.  ((never much liked oysters anyway))

    1. There were all sorts of worries about whether the Van Allen Belts would fatally irradiate astronauts, and Earl Holliman did that Twilight Zone episode about an astronaut losing his mind in a simulated 20 day trip to the moon.

      There was endless speculation about whether people could survive in orbit. 

  4. Why does it have to be a man and a woman?  Why can’t it be a man and a man or a woman and a woman?

    1. They probably want data on both a man’s physiology and a woman’s physiology after the long trip.

  5. Shitsulation takes a little of the polish off of “hot space sex.”  At least for me.

    1. For what its worth, I don’t think this means you’re going to have to smear the walls with feces on your trip to Mars.  You’re going to use your space toilet and it will get pumped into some cavity you can’t see.

          1. That’s a safe assumption. ;)
            I should have made explicit my caveat *assuming being near lots of fecal matter is a turn off.  Because that capsule is going to smell like space-farts.  And they’re the deadliest.  (Also I imagine any thrills gained by enacting one’s furtive couplings in rest-rooms are going to disappear when you live in a port-a-potty.)

        1.  Bradley, I am about to blow your mind, man. You know dirt? The stuff that you’ve walked on all your life? In fact, a synonym for “earth”? 100% worm shit, dude.

  6. I think the mental trauma caused by flying to Mars in a Hitachi Magic Wand lined with poo would be worse than any radiation.

    1. I find the notion of flying through space in an enormous sex-toy the furthest thing from traumatic.

      Chillin.  You?
      Flying giant space vibrator to Mars.

      But you’ve a valid point with the dirty walls by Hu Phlung Pu.

  7. Great. Thanks a lot. Thanks to this article, from now on I’m going to think of that bulbous chamber  tacked to the front of the capsule as a giant toilet float.

    1.  Riffing on A&E, I always thought James White’s Sector General books would make a great TV show.

  8. However assured that the recycled water was clean, I’d still have the suspicion that I could smell a hint of poo in every sip. 

  9. Sleight of hand bullshit headline. Using waste as radiation shielding is just as a replacement for the non-recycled fraction of the the thick wall of water that’s actually the main shield. That two-foot thick wall of water would be enormously expensive to ship into space from Earth. The excremental increment of radiation protection would be tiny, but this shit gets attention.

    1.  The first alien ship that fires upon it is gonna get a biiiiiiiiiiiiiiiiiiiiiiiiig surprise.

  10. Scotty we need more power to the shields!

    I’m tryin’ captin, but she ain’t got no more in her!

    Bonus for Scotty being a brand of TP.

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